From Killing Floor Wiki
A player who intentionally tries to disrupt or ruin other players' gameplay is known as a griefer. Some griefers try to make their intentions unclear so that they can harm the team indefinitely without being kicked.
Griefing acts to majority of players
- Blocking Trader entrances (the action is not possible anymore as player collision is disabled during trading).
- Unwelding or destroying doors that the team wants welded.
- Purposely running in front of an explosive weapons user to cause self-damage.
- Purposely enraging the Fleshpound with a weak weapon so that it will damage or kill its target.
- Being useless by following team-mates around for protection while not assisting them at all.
- Blocking players to prevent them from backpedaling away from specimens.
- Using a shotgun to knock team-mates off edges.
- Trapping team-mates in areas by body blocking.
- Welding doors to block team-mates.
- Team-killing on purpose (on friendly fire servers).
- Firing explosives at specimens that are close to team-mates, creating opaque smoke clouds that may annoy players by obstructing their view.
- Kiting the final specimen indefinitely while the rest of the team is waiting at the trader for the round to end.
- Firing flamethrower at fleshpounds/scrakes and sirens, which will obstruct the view of the sharpshooter who could take them down quicker.
- Purposely killing the last specimen when the team wants to keep it alive.
- Abusing server privileges (Ie. vote kick abuse)
- Purposely idle and afk in lobby before session begins taking up space and prevent games from starting.
Griefing acts to some players
- Abusing bugs.
- Spamming voice commands.
- Abusing players
- Farming perks on an easy map.
- Going "Rambo" -- killing the majority of specimens, not helping team-mates, and not donating cash to those in need. Although not an act of grief, it is disliked by most of the community.
- Not giving excess money to players even if the player has a surplus.
- Picking up the weapon of a fallen teammate, and not giving it back after the round when asked by the original owner. While not an act of grief, this behavior is still annoying, especially if the weapon is expensive and/or off-perk to the player.
- "Slot reserves"/ "clan member priority" although many servers and clans have that policy it's not classified as griefing but it's frowned upon.